1 conduit? 9/8/10 ELECTRICAL CONSISTENCY MEETING Code Consistency Questions 1. Can branch circuits of different services be installed in the same Yes, see 300.3(C)(1) for conductors of different systems rated 600 volts, nominal, or less that states, Conductors of circuits rated 600 volts, nominal, or less, ac circuits, and dc circuits shall be permitted to occupy the same equipment wiring enclosure, cable, or raceway. All conductors shall have an insulation rating equal to at least the maximum circuit voltage applied to any conductor within the enclosure, cable, or raceway. See 300.3(C)(2) for over 600 volt, nominal, conductors occupying the same equipment wiring enclosure, cable, or raceway with conductors of circuits rated 600 volts, nominal, or less which states, conductors of circuits rated over 600 volts, nominal, shall not occupy the same equipment wiring enclosure, cable, or raceway with conductors of circuits rated 600 volts, nominal, or less unless otherwise permitted in (C)(2)(a) through (C)(2)(e). The provisions of (C)(2)(a) through (C)(2)(e) were discussed. 2. Is it permissible to land my grounding electrode conductor in a fieldinstalled lug on either the inside or outside of the bottom of the service panel? No, unless it s listed for the use. See (A) that states, A premises wiring system supplied by a grounded ac service shall have a grounding electrode conductor connected to the grounded service conductor, at each service, in accordance with (A)(1) through (A)(5). Section (A)(1) states, The connection shall be made at any accessible point from the load end of the service drop or service lateral to and including the terminal or bus to which the grounded service conductor is connected at the service disconnecting means. Also, see that states, Nonconductive coatings (such as paint, lacquer, and enamel) on equipment to be grounded shall be removed from threads and other contact surfaces to ensure good electrical continuity or be connected by means
2 of fittings designed so as to make such removal unnecessary. Also, see 300.6(A) that states, Ferrous metal raceways, cable trays, cablebus, auxiliary gutters, cable armor, boxes, cable sheathing, cabinets, metal elbows, couplings, nipples, fittings, supports, and support hardware shall be suitable protected against corrosion inside and outside by a coating of listed corrosion resistant material. Both panelboard and switch equipment come with or have available neutral (grounded conductor) kits and provisions, which are listed for specific applications. 3. Is redundant grounding required in a feeder to a 200-ampere panel in a critical care area in a hospital? No, as this is strictly a branch-circuit requirement covered in However, (D), panelboard grounding and Bonding states, Where a grounded electrical distribution system is used and metal feeder raceway or Type MC or MI cable that qualifies as an equipment grounding conductor in accordance with is installed, grounding of a panelboard or switchboard shall be ensured by one of the following bonding means at each termination or junction point of the metal raceway or Type MC or MI cable: (1) A grounding bushing and a continuous copper bonding jumper, sized in accordance with , with the bonding jumper connected to the junction enclosure or the ground bus of the panel (2) Connection of feeder raceways or Type MC or MI cable to threaded hubs or bosses on terminating enclosures (3) Other approved devices such as bonding-type locknuts or bushings Concerning branch circuit redundant grounding requirements of , Code-Making Panel 17, currently Code-Making Panel 15, stated in their substantiation to Proposal to the 1996 NEC that, the intent of (a) is to provide two separate grounding paths the metal raceway and the conductor. They also stated that, Type MC Cable with two paralleled equipment grounding conductors [one green insulated and the other green with yellow stripes insulated] does not satisfy the requirement of Section (a). Also, see Code- Making Panel 17 s panel statement to Proposal to the 1996 NEC that states, The addition of a second equipment grounding conductor does not introduce a redundant path, it merely increases the capacity of the equipment grounding conductor. The intent
3 of Section (b) is to provide two separate means of grounding the raceway and the conductor. 4. 1) Can more than one receptacle in a laundry room be on the required laundry circuit? 2) If the laundry equipment (washer/dryer) is in one room but the owner irons clothes in another room, can the circuit go to the two rooms? 1) Yes, see (F) that states, In dwelling units, at least one receptacle outlet shall be installed for the laundry. See (C)(2) that states, In addition to the number of branch circuits required by other parts of this section, at least one 20-ampere branch circuit shall be provided to supply the laundry receptacle outlet(s) required by (F). 2) No, (C)(2) requires at least one 20-ampere branch circuit shall be provided to supply the laundry receptacle outlet(s), and it states, This circuit shall have no other outlets (A) and basically state the any circuit leading to or through dispensing equipment and each dispensing device shall be provided with means to remove all external voltage sources. Does this include intrinsically safe circuits? NO. If the intrinsically safe circuit(s) are properly installed in accordance with article 504 of the NEC then it is not necessary to include them in the requirements of (A) and For further clarification, consult NFPA 30A section 6.7 exception. 6. Can the same equipment grounding conductor be used for the pool motor and the pool lights? Someone told me we need a separate EGC for each light and for the motor. Yes, No, and maybe. The pool motor must be separate from the pool lights; however the pool lights may be combined on the same equipment ground with restrictions. See Underwater Luminaires (Lighting Fixtures), subsection (F) (3) Conductors, that states, Conductors on the load side of a ground-fault circuit interrupter or of a transformer, used to comply with the provisions of (A)(8), shall not occupy raceways, boxes, or enclosures
4 containing other conductors unless one of the following conditions applies: (1) The other conductors are protected by ground-fault circuit interrupters, (2) The other conductors are grounding conductors, or (3) The other conductors are supply conductors to a feed-through type ground-fault circuit interrupter. Also see subsection (F)(2) Equipment Grounding, that states, Through-wall lighting assemblies, wet-niche, dry-niche, or no-niche luminaires (lighting fixtures) shall be connected to an insulated copper equipment grounding conductor installed with the circuit conductors. The equipment-grounding conductor shall be installed without joint or splice except as permitted in (F)(2)(a) and (F)(2)(b). The equipment-grounding conductor shall be sized in accordance with Table but shall not be smaller than 12 AWG. Section (F)(2)(a) states, that where more than one underwater luminaire (lighting fixture) is supplied by the same branch circuit, the equipment grounding conductor, installed between the junction boxes, transformer enclosures, or other enclosures in the supply circuit to wet-niche luminaires (fixtures), or between the field-wiring compartments of dry-niche luminaires (fixtures), shall be permitted to be terminated on grounding terminals. Section (F)(2)(b) states that the underwater luminaire (lighting fixture) is supplied from a transformer, ground-fault circuit interrupter, clock-operated switch, or a manual snap switch that is located between the panelboard and a junction box connected to the conduit that extends directly to the underwater luminaire (lighting fixture), the equipment grounding conductor shall be permitted to terminate on grounding terminals on the transformer, ground-fault circuit interrupter, clock-operated switch enclosure, or an outlet box used to enclose a snap switch. As to motors, see (A)(1) Wiring Methods, General that states, The branch circuits for pool-associated motors shall be installed in rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit, or Type MC cable listed for the location. Other wiring methods and materials shall be permitted in specific locations or applications as covered in this section. Any wiring method employed shall contain an insulated copper equipment-grounding conductor sized in accordance with but not smaller than 12 AWG. Also, see (A)(4) One-Family Dwellings that states, In the interior of one-family dwellings, or in the interior of accessory buildings associated with a one-family dwelling, any of the wiring methods recognized in Chapter 3 of this Code that comply with the provisions of this paragraph shall be permitted. Where run in a cable assembly, the equipment grounding conductor shall be permitted to be uninsulated, but it shall
5 be enclosed within the outer sheath of the cable assembly. Also, see (A) Area Lighting, Receptacles, and Equipment, Receptacles, subsection (5) GFCI Protection that states, All 15- and 20-ampere, single-phase, 125-volt receptacles located within 6.0 m (20 ft) of the inside walls of a pool shall be protected by a ground-fault circuit interrupter. Receptacles that supply pool pump motors and that are rated 15 or 20 amperes, 125 volts through 250 volts, single phase, shall be provided with GFCI protection. 7. I have installed a dedicated 20-ampere branch circuit to a microwave receptacle mounted in the cabinet space above the microwave oven. On the finish I installed a 15-ampere duplex receptacle. The inspector red tagged the job, and requested that I install a single 20- ampere receptacle. Is this a violation and if so what section of the 2008 NEC applies? First, the NEC does not define the term dedicated branch circuit. See Article 100, page 25 that states an individual branch circuit is, A branch circuit that supplies only one utilization equipment. Section (B)(1) states, A single receptacle installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit. Note that the exceptions to this section do not bear in this installation. Also, note that Section (B)(1) does not require an individual branch circuit to serve a single receptacle exclusively. Section (B)(3) states, where connected to a branch circuit supplying two or more receptacles or outlets, receptacle ratings shall conform to the values listed in Table (B)(3). Table (B)(3) allows receptacle ratings of both 15- and 20-ampere on a 20-ampere rated circuit. Also, note that (B)(2) for cord-and-plugconnected loads requires that, where connected to a branch circuit supplying two or more receptacles or outlets, a receptacle shall not supply a total cord-and-plug-connected load in excess of 12-amperes for a 15-ampere rated receptacle supplied by a 20-ampere rated circuit and 16-amperes for a 20-ampere rated receptacle supplied by a 20-ampere rated circuit. Also, see (A)(1) that states, the rating of any one cord-and-plug-connected utilization equipment shall not exceed 80% of the branch-circuit ampere rating, which compliments the requirements in (B)(2). Also see (A) that states, the rating of an individual branch circuit shall not be less than the marked rating of the appliance or
6 the marked rating of an appliance having combined loads as provided in See that states, Each electric appliance shall be provided with a nameplate giving the identifying name and rating in volts and amperes, or in volts and watts (B)(1) states, in addition to the marking required in , the marking on an appliance consisting of a motor with other load(s) or motors with or without other load(s) shall specify the minimum supply circuit overcurrent protective devices. Therefore, a 15 ampere rated duplex receptacle is acceptable where the load is limited to 12 amperes or less and a 20-ampere rated receptacle would be required for loads exceeding 12-amperes up to 16- amperes. If the microwave range also has a range hood built into it, look at (B)(4) that states, range hoods shall be permitted to be cord-and-plug connected with a flexible cord identified as suitable for use on range hoods in the installation instructions of the appliance manufacturer, where all of the following conditions are met: 1) The flexible cord is terminated with a grounding-type attachment plug where the range hood is not identified as one utilizing a system of double insulation, 2) The length of the cord is not less than 18 inches and not more than 36 inches, 3) receptacles are located to avoid physical damage to the flexible cord, 4) the receptacles is accessible, and 4) the receptacle is supplied by an individual branch circuit. 8. Is it permissible to parallel MC Cable? What about the sizing of the equipment grounding conductor? Yes, MC Cable can be paralleled as permitted in Article and The sizing if the equipment grounding conductor is done in accordance with 310.4(E). There are some manufacturers who have listed MC cables made specifically for paralleling. 9. The secondary side of a step-down transformer is fed with steel flex and attached to a panelboard, with the neutral and grounding electrode conductors landed at the transformer. What are my bonding and /or grounding requirements in my steel flex and to the panel? See Grounding Separately Derived Alternating-Current Systems. (A) Grounded Systems that states, A separately derived ac system that is grounded shall comply with
7 250.30(A)(1) through (A)(8). Except as otherwise permitted in this article, a grounded conductor shall not be connected to normally non current-carrying metal parts of equipment, to equipment grounding conductors, or be reconnected to ground on the load side of the point of grounding of a separately derived system (A)(1), System Bonding Jumper states, An unspliced system bonding jumper in compliance with (A) through (D) that is sized based on the derived phase conductors shall be used to connect the equipment grounding conductors of the separately derived system to the grounded conductor. This connection shall be made at any single point on the separately derived system from the source to the first system disconnecting means or overcurrent device, or it shall be made at the source of a separately derived system that has no disconnecting means or overcurrent devices. However, see Exception No. 2 that states, A system bonding jumper at both the source and the first disconnecting means shall be permitted where doing so does not establish a parallel path for the grounded conductor. If the steel flex meets all the requirements of ; then you may pull three hots and the grounded conductor (neutral) to the secondary panel where the grounded conductor (neutral) is isolated from the can. If the steel flex does not meet the requirements of an equipment bonding jumper must be pulled with your three hots and the grounded conductor (neutral) to the secondary panel and the grounded conductor (neutral) is isolated from the can. 10. I recently inspected a job where the electrician installed the grounded conductor and the grounding conductor in the same terminal of the panelboard. Is this a violation? Yes, see and 110.3(B). Section states, Each grounded conductor shall terminate within the panelboard in an individual terminal that is not also used for another conductor. However, also see the exception that states, Grounded conductors of circuits with parallel conductors shall be permitted to terminate in a single terminal if the terminal is identified for connection of more than one conductor. 11. Is a service installed correctly if a meter and service disconnect breaker are installed on a pedestal 100 feet from the house and bonded at the pedestal and a four-wire feeder piped directly into a MLO panel located 20 ft inside the house?
8 No, the service may be 100 feet from the house however see, that states, The disconnecting means shall be installed either inside or outside of the building or structure